Determining original FBSD version

[Gerard Samuel]

I plan on making the move to 5.3 on boxes running 4.10
via a fresh install.
The thought came to me as to what was the original version of
FreeBSD did I install on those boxes.
Usually I upgrade the boxes via build/install world.
If there is way to find out, that it would be interesting to know.
If not, no big deal, as its an absent minded thought...

Thanks